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List:       boost-users
Subject:    Re: [Boost-users] making a geometry half closed
From:       Barend Gehrels <barend () xs4all ! nl>
Date:       2014-01-27 17:11:07
Message-ID: 52E6932B.8040407 () xs4all ! nl
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Hi,

Mateusz Łoskot wrote On 27-1-2014 10:40:
> On 26 January 2014 23:00, Adam Wulkiewicz <adam.wulkiewicz@gmail.com> wrote:
>> The coordinates aren't floating points. Maybe using right-1 for <max_corner,
>> 0> and bottom-1 for <max_corner, 1> could work? It probably depends on the
>> use case.
> I also think offsetting right and bottom segments would do the trick,
> as long as the coordinates are discrete.


Yes, it is a good idea to consider but it really depends on the 
use-case, indeed.

For example: calculating the area would then go quite wrong. And 
calculating the perimeter would go a bit wrong. But within might succeed.

We follow OGC's model for all geometries, so there is an interior, there 
is a boundary and there is an exterior. Points can be placed "on 
boundary" or inside or outside. A segment-crossing goes via the 
boundary. If there is at one side no boundary, the underlying 
assumptions fail.

So that's why I wrote: "it's not implemented". But you can try to do 
things of course, it will compile.

Regards, Barend


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